Sanding device



Sept. 15, 1964 D. v. FILDES 3,148,487

SANDING DEVICE Filed June l2, 1965 2 Sheets-Sheet 1'/////////////////////////////,l'li F 1 Zilli/111111 17. y I l rA 9o 8075 9056 Tij" E 56 9080 75 90 l 05 ATTORNEY s@Pt- 15 1954 D. v. FILDEs3,148,487

SANDING DEVICE 30a. 90a .F1 7. E 90a.

/ ATTORNEY United States Patent O 3,148,487 ANDl'NG DEVHCE Desmond V.Fildes, 163.4 Cleveland St., Grafton, Ohio, assigner of one-half to MittWiiheim, Weliington, Ohio Filed .lane 12, 1953, Ser. No. 287,293 14Slaims. (Cl. 51 175) This invention relates to improvements in sandingdevices and more particularly to an improved sander for sanding flatsurfaces wherein the sanding means partakes of a reciprocatory motion.

Heretofore there have been proposed many means for the sanding of flatsurfaces. These usually comprise an electric motor which is connected bya linkage to reciprocate one or more pads having an abrasive thereonwhich are in engagement with a dat surface, such as a floor, with areciprocatory or orbital motion. One such apparatus is illustrated inPatent No. 2,956,379.

Machines of the above type had certain deciencies in operation whichincluded the fact that the abrasive material became loaded with debris,particularly where the surface being sanded had been varnished or was ofa resinous material. This loading of the abrasive surface was largelydue to the fact that the surface of the above was inadequately cooled.Furthermore this loading was not necessarily uniform over the entiresurface since a portion could become loaded and result in a scoring ofthe article being sanded and making the abrasive useless even though itwas by no means worn out.

Another disadvantage of the prior art resided in the fact that thesurface to be sanded, particularly when that surface was newly laid, wasnot necessarily at but had inequalities, such as boards of unequalthickness or those that were slightly warped. When such surfaces weresanded, the high spots were sanded but the low spots were not.

Such previous devices required the frequent renewal of the abrasive,which was not only expensive but timeconsuming. Due to the above, itfrequently happened that the abrasive was not renewed as soon as itshould have been renewed, with the result that the Work done after theabrasive should have been renewed, was of an inferior quality.

In addition to the above, the prior devices created a large amount ofdust and failed :to adequately collect the dust, thereby making workingconditions undesirable and requiring a subsequently large amount ofcleaning to remove the dust.

The present invention contemplates a sander, particularly useful in thesanding of wood floors but not necessarily limited thereto, wherein theabrasive life is greatly prolonged, the surface sanded can be irregularand in spite of the irregularities the sanding may proceed at a muchhigher rate of speed. In addition, the amount of dust created is reducedto a minimum and efficiently collected in a suitable bag for subsequentdisposal.

Still other advantages of the invention and the invention itself willbecome more apparent from the following description of an embodiment ofthe invention, which description is illustrated by the accompanyingdrawings and forms a part of this specication.

In the drawings:

FIG. l is a reduced perspective view of a complete sander constructedaccording to the invention;

FIG. 2 is a fragmentary view on a larger scale, partly in elevation andpartly in section, of the lower end of the sander;

FIG. 3 is a fragmentary bottom plan view thereof;

FIG. 4 is a section taken on the line 4 4 of FIG. 3;

FIG. 5 is a bottom view, on an enlarged scale relative to the otherdrawing of one of the sanding elements, with ice certain parts brokenaway to show the underlying structure;

FIG. 6 is a section taken on the line 6 6 of FIG. 5;

FIG. 7 is a section taken on the line 7 7 of FIG. 5;

FIG. 8 is a fragmentary section taken on the line 8 8 of FIG. 5;

FIG. 9 is a section taken on the line 9 9 of FIG. 5; and

FIG. l() is an enlarged section of a fragment of FIG. 7.

Referring now to the drawings, throughout which like parts aredesignated by like reference characters, as best shown in FIG. 1, thesander of the invention includes a base 10 upon which is supported anupright motor and suction fan 11 which is arranged to draw the dust fromthe sanding member 12 and discharge the same into a bag 13. A suitablehandle 14 is pivotally connected to the base iti whereby the device maybe moved backward and forward over the surface to be sanded.

As best shown in FIG. 2, fthe base 1t) comprises an upper iiat surface15 on which the motor and fan housing 11 are mounted and a dependingperipheral skirt 10a, the lower end of which is provided with aperipheral groove having a resilient bumper 10b therein.

A motor is contained in the lower end of the housing and has a shaft 16mounted in a bearing 17 and carrying an eccentric 18 on which a pair ofdrive links 20 are journalled. The drive is to the reciprocatory memberswhich are reciprocated under the platform and each of which includes anupper plate 25, and a lower plate 27 held in rigidly spaced relationthereto and under which the pressure sander members are mounted. Thespace between the plates is enclosed by a housing 26 which forms aplenum chamber connecting a vacuum drawing means to the sander members.

Inverted U-shaped brackets 3i) are secured to the underside of the base15 and support rods 31 on which support members 32 are reciprocablyjournalled. The support members 32 are in turn secured to the upper sideof the upper plate 25. As can be seen from FIG. 6, two of the supportmembers are provided for each of the reciprocatory members disposed atopposite ends thereof. The links 20 have arms 20a which are connected tothe upper plates 25 by vertical pivots 32 mounted on top of the plateand extending through eyes in the ends of the arms.

When the motor is operating, the eccentric 18 revolves and reciprocatesthe links and they in turn move the upper plates to and fro, on the rods31, in opposite directions.

Each of the plenum chambers 26 comprises an upper rectangular plate 26ahaving a peripheral flange 26h which telescopes inside a secondperipheral ange 26C on a lower rectangular plate 25d to provide a hollowbox-like chamber closed on all Sides.

The upper chamber member 26a-2611 is secured to the upper base plate 2Sby screws, not shown, which are threaded into the plate 25 with theirheads engaging the underside of the plate 26a.

The lower chamber member 26e-260. is secured to the lower plate 27 byscrews 40, the heads of which are Vcountersunk into the lower face ofthe plate 27 with the Shanks extending through the plate 26d and intospacers 4l. The upper ends of the spacers 41 support spring guide strips42, the purpose of which will later be described, being held thereon byscrews 43 which are threaded into the spacers.

The two plenum chamber halves are secured in spaced relation to eachother and at the same time the load is relieved from the plenum chamberparts by columns which extend through the plates 26a and 26d and aresecured to the upper and lower plates 25 and 27, FIGS. 6 and 9. Thecolumns include an upper portion 45 0f cylindrical formation having anecked down upper end 45a which has a close fit in an aperture in theupper plate. The portion 45 is provided with a counterbore and thenecked down part is interiorly threaded. The extremity which projectsthrough the plate 25 is spun over at 45!) or staked to hold the samesecurely and rigidly to the plate 25.

The lower part of the column likewise consists of a cylindrical hollowbody 46 which extends through the lower plate 26d and has a necked downpart 46a which extends down into an aperture in the plate 27. In thisinstance, the aperture in the plate 27 has a beveled lower edge and theend 46a of the necked down part is spun over into contact therewith,whereby this column part is held securely to the base plate and flushwith or above the bottom surface of the plate 45.

The upper end of the column 46 is provided with a reduced portion 46hwhich has a close lit with the counterbore in the upper column part.

The parts are held together by cap screws 47 which extend through thebottom plate 27 and through the column parts and are threaded into theupper column part 45a. Thus the upper and lower base plates 25 and 27and the plenum chamber parts are held in xed spaced relation to eachother and the drive for reciprocating the sanding means has all theforces directed from the upper plate 25 through the stiff columns to thelower plate 27, which carries the sanding means. This provides a firm,rigid drive and relieves all the strain from the plenum chamber parts.

The sanding means includes a plurality of independently supportedpressure feet and a means for holding abrasive sheets in contacttherewith.

As can best be seen from FIGS. 7 and 8, the lower base plate 27 isprovided with a pair of spaced, parallel, longitudinally extendinggrooves 27a. These grooves may be of rectangular cross section and aredisposed equally spaced on opposite sides of the longitudinal centerline of the element. As can best be seen from FIG. 3, the longitudinalcenter lines of the reciprocatory elements extend transverse to thelongitudinal center line of the base 10. The shape of the base 10 ishowever a matter of choice since it could be square rather thanrectangular, as shown, or the device could be wider than it is long.

As best shown in FIGS. to 8, each pressure foot includes a rectangularbase 50, one end of which is provided with an inverted U-shaped edgepart Sila which tits loosely in the groove 27a. The outer end of eachbase Si? is provided with a hook-shaped end Stlb formed by bending theend at 9 to the base and then backward at its extremity 90, to overliethe top edge of the base plate 27. The length of the connecting part 50bis such that a clearance space is provided between the base 50 and theplate 27, whereby the outer extremity may move toward and from the basewith the part 50a pivoting in the channel 27a.

A keeper is provided which comprises an elongated strip 53 havingupwardly extending edge portions 53a which extend into parts 59a. Theengagement of the edge portions 53a with the pressure feet is such thatthe feet are held in position but are free to rotate about the edgeparts 53a. The lower face of each member 59 has an inverted U-shapedsocket 55 welded thereto and each of these sockets has a substantiallysquare block 56 of highly resilient material vulcanized or otherwisecemented there- Each of the blocks 56 is provided with a centralaperture 56a which extends upward through the block and is concentricwith an opening 5tlg] in the plate 5t). The edge of the opening isbeveled to provide a seat for a coupling and socket 6l). The opening 56ais of smaller diameter than the opening 55d. Extending from the centralopening 56a are a pair of grooves 56b which diverge from each other andextend to the outer edge of the block. Although the blocks are shown asbeing of a length equal to the distance between the flanges 55 of thesocket, they CII could overhang the socket, particularly on the outeredge.

Means is provided to resiliently hold the pressure members tilteddownward to the limit of their movement as determined by the engagementof the ange 50b with the top of the plate 27 and at the same time permittilting movement of the members about their pivots in the channels 27a.rThis same means also provides a duct means for drawing air through theapertures 56a and channels 55h into the plenum chamber 26. This includesa lower coupling and spring socket member 60 having a cylindrical outerbody, the lower end of which curves to provide a seat engaging part 60aand having at its lower extremity a hollow stem tlb, the end of which isrounded olf at its end. The seat engaging part 60a seats on the seat 50din the top of the plate 50 and the stem 60b is forced into and providesa tight t with the wall of the aperture 56a in the rubber or resilentblock 56. The rounded end facilitates the insertion of the coupling intothe resilient block 56.

The aperture in the plate 27 is provided at its upper end with a seat inwhich an O ring 61 is disposed. The O ring is held in place by the plate26d which lies over the vertical mid-section of the O ring. The body 60of the coupling has a sliding engagement with the O ring. The aperturein the plate is sufciently large and the lower end is relieved asindicated in order that the coupling 60 may tilt relative to the plate27 when the pressure member moves about its pivot. It will thus be seenthat air entering through the duct 56a is conducted through the couplinginto the interior of the plenum chamber by virtue of the stem 60!)sealing in the block and the body 60 seating with the O ring.

Pressure is exerted on the coupling 60 by a spring 63, the lower end ofwhich seats on the interior of the coupling 60 and the upper end ofwhich is engaged by a cap 65 which extends through an aperture in thestrip 42, and has a ange 65a in engagement with the underside of thestrip. The cap is provided with an end opening 65a, the end of the capbeing spaced from the wall 26a of the plenum chamber.

Thus the pressure member may move up and down within the limits definedby the flange 50b and base 50 against the pressure of the spring 63.

There are two rows of these assemblies for each of the sanding members12, FIG. 5, one row extending toward the outer edge and the other towardthe inner edge. The size and number of pressure feet in the rows may bevaried. It has been found, however, that for a sanding member 14 incheslong, eight of these feet, approximately 1% inches wide, provide ahighly satisfactory manner of operation.

The actual abrasive material of each of the reciprocating members iscomprised of two strips of a exible base material having an abrasivesurface on one side, such as sandpaper. Each strip is disposed over arow of the feet and clamped at its innermost edge by a centrallydisposed clamping means. The outer edges of the strip are free to moveon and with the feet.

The clamping means, FIGS. 7 and 8, includes a plu rality of clips 70, inthis instance three are shown, which extend transversely across thepressure feet clamp bar 53 and are held in place by screws 71 whichextend through openings in the clips and are threaded into threadedbushings 72 disposed in and staked in apertures in the lower base plate27. The clips are held in iixed, longitudinally spaced position by anarrow strip 73 which extends longitudinally of the head and over facesof the clips.

The clips are provided with flanges 7Gb which extend downward onopposite sides of a heavy fabric strip 75 and have tongues 70e which arebent over and engage with the bottom side of the fabric to hold itsecurely in place. The strip 73 also acts as a shim and backing for thelongitudinal center zone of the fabric 75 and amena? causing the fabricto assume a curvature, as shown in FIG. 8.

The abrasive clamping bar 80 is a strip of rigid metal of curvedtransverse cross section which extends longitudinally along a zoneequally spaced about the center line of the fabric strip 75 with thelongitudinal outer edges pressing against the fabric. The curvature ofthe strip 75 prevents the abrasive from being cut or broken, due to theclamping action and also increases the life of the strip 75. The stripis held against the fabric by means of bolts 81 and springs, the headsof the bolts are countersunk into the face of the strip 80 and theshanks extend through the strips 75, through openings in the strip 73,the clamp bar 70, the keeper strip and the base plate 27.

The end of each shank has a locking type nut 82 which engages with theend of a helical spring 83, the other end of which engages with the topsides of the clamp brackets 70. The openings for the shank of the boltare suiciently large that the clamp bar tl may be tilted by theinsertion of suitable tools in holes Sila in the clamp bar, whichenables the bar to be tilted, the shank swinging to the right or left,as viewed in the gures, to allow one edge or the other of the clamp tobe raised and the sandpaper 90 inserted under the edge between theupturned edge and the fabric.

The spring and bolt assembly is sealed against the ingress of air atthis point by a rubber cap 91 which surrounds the same and is cementedinto the hole in the lower face plate around the spring and bolt.

As stated, the abrasive comprises a rectangular strip 90 which isclamped in place by the clamp means, the clamp means being tilted toraise one edge and the strip inserted between the clamp means and thefabric. This provides a resilient cushioned means for holding theabrasive strip which allows the strip to bend without breakage. Thestrip extends under the pressure feet and is provided with a series ofapertures 99a which register with the aperture 56a in the feet.

It is preferred that the strip be a continuous piece of material whichextends under the pressure feet and also bridges the small gap betweenthe adjacent edges of the pressure feet. It is contemplated, however,that in some instances and for some purposes the abrasive strip may beslitted with the slits disposed opposite the adjacent edges of thepressure feet, whereby the tongues formed thereby may move in anindependent fashion.

In operation when the device is supplied with power, the motor in thelower part of the housing 11 operates to rotate the shaft 16 and throughthe eccentric 18 and links Ztl-20a the reciprocable members arereciprocated on the shafts 31 laterally as viewed in FIG. 2. This causesthe abrasive to be reciprocated in contact with the lloor. If the flooris a board flooring, the machine is placed in contact with the floor andmoved lengthwise with the boards of the floor. Should one board behigher than the other, the high board causes one or more of the pressurefeet to move upward due to the concentration of weight on that member,also allowing the sandpaper in that zone to move upward. It will beappreciated that under such conditions the discrepancy in height is notvery great and therefore this movement is slight. It has been found,however, that by providing this type of flexibility the high boards andthe low boards may be sanded with a complete sanding of all the boardsto such an extent that the inequalities in height, although notcompletely eliminated, are not apparent to the observer. Thus if oneboard out of eight should be lower, it would not be necessary to sanddown the other seven to the level of the one, thus the time and amountof material removed is greatly reduced.

Furthermore by making the strip of continuous material, should one boardbe higher or lower than the others, the pressure feet may raise orlower, at the point where the transition of the sandpaper from a lowboard to a high board takes place, the sharp edges are removed.

It is pointed out that the strength or compressibility of the springs 63is correlated with the weight of the machine such that the normal weightof the machine may cause some compression of the springs, whereby thefeet take a position somewhere between their limits of upward movementas defined by the hooked ends 50h. it is contemplated, however, that thesprings may be sufficiently stiff that they are not compressed by theweight of the machine. ln this instance if the weight is concentratedover one of the feet 56 it would still rise. Furthermore if it wasdesired that the normal state be one of a slight compression of allsprings, then weights could be placed on top of the platform 11i and theweight of the machine supplemented by these weights to cause the desiredamount of compression. it may be desirable in particularly hard wood tomake the springs 63a very stiff and then to add weights to increase theentire pressure on the floor by the machine and thus speed up thesanding operation.

At the same time that the drive motor is turned on a fan motor in theupper housing is turned on. This causes a suction or vacuum which isdrawn upward through a chamber lill? surrounding the lower motor intothe upper fan housing and discharge into the bag 13 in a manner wellknown in the art. The duct lltltl, FIG. 4, connects by a port 191 tomanifolds 102 disposed on the underside of the base 1t?. Each of thesemanifolds is provided with an elongated inlet port 103 which registerswith an outlet port 1134 in the upper plates 25 of the reciprocatingmembers.

Thus air is drawn through the holes a in the sandpaper, through theducts 56a in the resilient pads 56 and through the coupling et) into theplenum chamber 25, by way of the ports 104 and manifold 162 andeventually discharged into the bag. At the same time air as well as dustis drawn in along the diverging grooves 56!) to the duct 55a from theouter edge of the sandpaper strips. This not only greatly reduces theamount of dust which escapes to the surrounding room but also cools boththe sandpaper and the pressure feet.

In addition the vacuum causes the sandpaper to be drawn more closely tothe outer edge surfaces of the pressure feet and holds it more tightlyin place at its outer edges.

1t is contemplated that the strips of abrasive be made with two lines ofholes 91M, one being spaced from the outer edge, as shown in FIG. 5, andthe other line having a similar spacing from the inner edge. When theouter edge portion becomes worn, it may be unclamped and turned aroundand the other edge used.

The cooling of the sandpaper prevents the same from becoming coated withresin and materially increases its life. The suction of the dust fromalong the edge of the sandpaper materially reduces the dust thrown outinto the room.

It will be noted that the couplings 66 not only serve as seats for thesprings 63 and ducts for transmitting the dust laden air to the plenumchamber but also hold the pressure feet against longitudinaldisplacement in the grooves 27a. The feet may be removed by pressing thecouplings upward so that the reduced part tlb is disposed above the body5u and the feet slid outwardly toward the end.

The air through the couplings 60 is also upward through the springs andeven though the springs may be considerably compressed, the air canescape through the openings 65a at the top. Thus the springs are cleanedby the passage of air therethrough. A

lt will be particularly noted that the entire clamp assembly isremovable as a unit by taking out the screws 71. It may thus be easilyreplaced when worn. The camber given to the strip 75, as stated,increases the life of the abrasive as well as the fabric itself.

ln the previous devices conformance with the irregularities of the oorwas accomplished by making the pressure pads soit. Under theseconditions the sanding was inadequate and took too long. When the padswere made hard they did not conform to the floor and therefore parts ofthe floor were not sanded. The above described invention providesconformance with the door and elicient sanding.

It is pointed out that the action of the pressure feet is materiallydifferent than prior devices. As the feet move upward against the springpressure, which they do when the device is in operation, due to thefixed pivot 50a and the short length of the lever arm, which is the bodyof the pressure member, the sandpaper is forced into the oor with anarcuate movement, which is in addition to the reciprocatory movement bythe drive mechanism. Therefore at the start of this reciprocatorymovement, the outer edges of the pressure feet have the outermost edgeor toe 90b in engagement with the door and as the feet move upward thecontact is moved backward toward the inner edge of the blocks 56.

Having thus described the invention, in an embodiment thereof, I amaware that numerous and extensive departures may be made therefromwithout departing from the spirit of the invention as defined in theappended claims.

I claim:

l. A device of the class described including a base, at least onereciprocatory member reciprocably supported below the base, saidreciprocatory member comprising a pair of members connected to eachother, one above the other, in rigidly spaced relation to each other,means enclosing the space between said members to provide a plenumchamber and means for drawing a vacuum supported by said base andconnecting means connecting said vacuum means to said plenum chamber,means for performing work on a surface supported from one of said pairof spaced members and arranged to be engaged with a surface upon whichwork is to be performed and reciprocated by said member, and duct meansconnecting said work performing means to said plenum chamber.

2. A device as described in claim l, wherein said work performing meanscomprises at least one resiliently mounted pressure foot, an abrasivematerial disposed between the pressure foot and the surface to be workedon.

3. A device as described in claim 2, wherein said pressure foot isformed with an air duct spaced from the edges and air grooves connectedthereto and extending to the outer edge of the foot and said abrasivemeans extends to the outer edge of said pressure foot, and said air ductis connected with said duct means.

4. A sander including a reciprocable member of generally rectangularformation having a plenum chamber, rows of pressure feet hingedlysecured to the underside of the reciprocable member near thelongitudinal center and with the feet in each row extending in oppositedirections to the longitudinal edge of said member, means connectedbetween each of the feet and said member to limit the movement of thefeet toward and away from the member, each of said feet having aresilient pad secured to the bottom thereof and extending to the outeredges of the feet on the edge opposite to the point of hingedconnections, said pads being formed with ducts extending through thepads intermediate the edges, air duct means for each of said pads forconducting air through the ducts to the plenum chamber comprising acoupling having an enlarged body reciprocably disposed in sealedrelation in the bottoms of said member and a reduced portion in sealingengagement with the opening in said pad, spring means supported at oneend within said plenum chamber and having the other end connected tosaid coupling under compression to urge said pressure foot downward awayfrom said member.

5. A sander including a reciprocable member of generally rectangularformation having a plenum chamber, rows of pressure feet hingedlysecured to the underside of the reciprocable member near thelongitudinal center and with the feet in each row extending in oppositedirections to the longitudinal edge of said member, means connectedbetween each of the feet and said member to limit the movement of thefeet toward and away from the member, each of said feet having aresilient pad secured to the bottom thereof and extending beyond theouter edges of the feet on the edge opposite to the point of hingedconnections, said pads being formed with ducts extending through thepads intermediate the edges, air duct means for each of said pads forconducting air through the ducts to the plenum chamber comprising acoupling having an enlarged body reciprocably disposed in sealedrelation in the bottoms of said member and seated on said foot and areduced portion in sealing engagement with the opening in said pad,spring means supported at one end within said plenum chamber and havingthe other end connected to said coupling under compression to urge saidpressure foot downward away from said member.

6. An appaartus as described in claim 5, wherein said support means forsaid spring means includes an apertured member disposed in said chamberand apertured cups are seated in said apertured member and said springsare seated in said cups'.

7. A sanding machine including a base, motor driven vacuum producing anddrive means supported above the base, a pair of reciprocatory memberssupported below the base and means for connecting said drive meansthereto for reciprocating them below the base, each of saidreciprocatory members comprising a pair of rectangular plates and meansto hold said plates in vertically spaced relation to each other, meansenclosing the space between said plates to provide a plenum chamber,duct means in said base connected to said vacuum producing means and -tosaid plenum chamber, sanding means carried by the lower of said platesand comprising a plurality of pressure feet each of which is hingedlyconnected to said plate spaced from the edge and extends outwardly atleast to the edge, means on each of said feet to limit the movementthereof relative to the plate, abrasive means connected at one edge tosaid plate spaced from the edge of the plate and extending outwardlyunder said pressure feet, said abrasive means comprising a stripextending lengthwise under said feet.

8. A device as described in claim 7, wherein said abrasive strip isslitted opposite to the juncture of said pressure feet to enableportions thereof to move with independent movement of the feet.

9. In a sander having reciprocatory members for reciprocating andsanding of a surface, support means for holding and exerting pressure onan abrasive material including a base member of generally rectangularformation, a plurality of pressure feet disposed in at least one row onthe base member, said feet comprising elements having one end hingedlyconnected to said base and extending outwardly toward the edge of thebase and movable toward and from the base, means to limit the movementof said feet relative to the base, spring means connected to the supportmeans and said feet for resiliently holding the feet away from the base,a sheet of abrasive material, clamp means for securing said sheet at oneedge near the hinge means and said sheet being held by the clamp meansand extending under said feet.

10. A device as described in claim 9, wherein said feet have resilientpads secured thereto.

11. A device as described in claim 9, wherein said clamp means includesa flexible strip of material extending opposite to said hinges for saidpressure feet and means for holding said strip in spaced relation to thepressure feet and a clamp bar comprising a rigid strip of metal andspring means for connecting said clamp bar to said strip holding meanswhereby the clamp bar may be tilted away from the flexible strip for theinsertion of the abrasive between the clamp bar and said exible strip.

l2. In combination with a vacuum producing means, a reciprocable sandingmeans connected thereto and including upper and lower spaced plates,means for reciprocating said plates, connecting means for holding saidplates in rigidly spaced relation to each other, closure means extendingbetween said plates and providing a plenum chamber, means connectingsaid vacuum means to said plenum chamber, said lower plate being formedwith a pair of longitudinally extending grooves spaced from each otherand from the edges and the center line of the plates, a plurality ofpressure feet each of which is formed to provide a socket at one endarranged to be disposed in one of said grooves, keeper means connectedto said plate and having a portion extending into said sockets on saidpressure feet for hingedly holding them in the grooves, said pressurefeet being disposed to provide multiple aligned feet in each row andextending outwardly toward the edge of said plate and individuallymovable toward and from the plate, means connected between the plate andthe pressure feet to limit the movement of the feet away from the plate,means to hold the feet resiliently away from the plate and to provideair ducts from the feet to the plenum chamber and to hold each 20 of thefeet against longitudinal movement in the grooves comprising a couplingfor each of ysaid feet extending in air sealing engagement andreciprocable through the plate and in sealing engagement with a pressurefoot, said coupling having a duct therethrough communicating with theplenum chamber and spring means connected with said coupling and saidupper plate arranged to press said coupling downward into engagementwith the pressure feet.

13. A device as described in claim 12, wherein each of said feet ismounted with a resilient pad and said pad has an opening intermediateits edges and said coupling eX- tends into the opening in sealingengagement therewith.

14. A device as described in claim 13, wherein the bottom of said pad isprovided with grooves extending from the opening and diverging from eachother to the outer edge of the pad.

References Cited in the tile of this patent UNITED STATES PATENTS1,492,659 Anderson May 6, 1924 1,681,648 Root Aug. 21, 1928 1,868,507Roos July 26, 1932 2,478,074 Atkin Aug. 2, 1949 2,764,852 Emmons Oct. 2,1956 2,929,177 Sheps Mar. 22, 1960 2,956,379 Statler Oct. 18, 196()

1. A DEVICE OF THE CLASS DESCRIBED INCLUDING A BASE, AT LEAST ONERECIPROCATORY MEMBER RECIPROCABLY SUPPORTED BELOW THE BASE, SAIDRECIPROCATORY MEMBER COMPRISING A PAIR OF MEMBERS CONNECTED TO EACHOTHER, ONE ABOVE THE OTHER, IN RIGIDLY SPACED RELATION TO EACH OTHER,MEANS ENCLOSING THE SPACE BETWEEN SAID MEMBERS TO PROVIDE A PLENUMCHAMBER AND MEANS FOR DRAWING A VACUUM SUPPORTED BY SAID BASE ANDCONNECTING MEANS CONNECTING SAID VACUUM MEANS TO SAID PLENUM CHAMBER,MEANS FOR PERFORMING WORK ON A SURFACE SUPPORTED FROM ONE OF SAID PAIROF SPACED MEMBERS AND ARRANGED TO BE ENGAGED WITH A SURFACE UPON WHICHWORK IS TO BE PERFORMED AND RECIPROCATED BY SAID MEMBER, AND DUCT MEANSCONNECTING SAID WORK PERFORMING MEANS TO SAID PLENUM CHAMBER.